Sir Alex Ferguson has pretty much seen all football has to offer so when a moment on the pitch causes him to laugh in bewilderment, as he did yesterday, it is fair to say something special has just happened. The Manchester United manager was sitting in a dug-out in Durban when the crowd of 500 people watching his team train roared in approval. Ferguson looked behind him to see what all the fuss was about and realised Wayne Rooney had just struck a shot from the halfway line with such power that it caused the crossbar of the far goal to shudder. Cue the chuckle and a shake of the head.

That Ferguson should be surprised by Rooney's talent is perhaps in itself, no surprise. Since arriving from Everton four years ago the forward has rarely been deployed in the central attacking role most observers agree is his best position, instead being pushed wide with Ferguson consistently justifying the selection as being the right one for the team. But relaxed by the warmth of a beautiful South African day and having witnessed Rooney's goal-scoring potential at its most vivid, the Scot has finally admitted he may have made a mistake.

"I think Wayne's best position is through the middle, either the front role or tucking in just behind," Ferguson said. "He is aggressive, has good pace and the courage to go in the box. There's no reason why he can't get a good supply of goals. But he may have benefited by having someone with more experience with him. That always happens with young strikers."

Rooney has been prepared to adopt unfamiliar roles to allow Cristiano Ronaldo to torment opponents, but last season the sacrifices undoubtedly blunted his edge. Despite scoring 20 goals for club and country, Rooney rarely stole the show for United and his England form suffered subsequently. Ferguson admits the time has come for him to stop taking advantage of the 22-year-old's versatility.

"We have to define Wayne's role better," he conceded. "He has never complained, which says a lot for the lad. He would play centre-half if I asked him to."

But Rooney was clearly annoyed at being deployed on the flanks to facilitate United's 4-3-3 formation last season and this was evident on those occasions when his frustrations resulted in the kind of flashpoints that leave him walking a disciplinary tightrope. The player once again allowed his temper to come to the fore on Saturday when he was booked for kicking out at an opposing player in a friendly against Kaizer Chiefs in Cape Town.

"At 22 he was never going to be the finished article. When you sign players at 18 it's for the long view," added Ferguson. "In a few years' time we will be saying that was brilliant business."

That Rooney's development, along with the rest of the United squad, will not be overseen by Carlos Queiroz clearly remains a matter of significant regret for Ferguson who yesterday spoke of the "legacy" the new head coach of the Portuguese national team has left following his two spells as assistant manager at Old Trafford.

"He was a great organiser and he was serious in his coaching. All the changes at the club in terms of sports sciences over the last few years have been down to Carlos," said Ferguson.

Looking ahead, he added: "Our coach Mike Phelan couldn't do much last season because of a knee problem but he's back now so the coaching side is no problem. What I have to decide is whether to bring someone in who is more experienced and can be there if I'm not. It is possible that person will be foreign because we have many Spanish- and Portuguese-speaking players. But whatever happens, Carlos's legacy must not be forgotten."

Asked if Queiroz could ever return, Ferguson said that having signed a four-year contract with the Portuguese FA such a scenario would be "difficult". It is of course conceivable that in four years' time Ferguson will himself no longer be at United and among those spoken of as a successor to the 66-year-old is the club's former striker, Mark Hughes. That seemed a real possibility while the Welshman continued to excel at Blackburn but, following his move to Manchester City, now appears less likely. Nevertheless, Ferguson is convinced "Sparky" made the right decision.

"He has left Blackburn at the right time because all the contracts are up next year," he said. "It was time for him to move on. He's proved himself there."

And what about Ferguson, what has he got left to prove? Having taken his trophy haul at United to 20 in 22 years, it would appear to be very little. But, in that respect, the club remains in the shadow of Liverpool - with 18 league titles and five European Cups to their name against United's 17 and three respectively - and it seems inconceivable a man as ambitious as Ferguson would be content to retire without having moved past them.

"There is no particular pressure in terms of trying to beat Liverpool," he insisted. "We proved the point about overcoming Liverpool when I came to the club. That was the time to do something about it."

Keep winning trophies and it will only be a matter of time before United establish all-time supremacy, is the message. And if the shaking frame of a Durban crossbar is anything to go by, that moment could come sooner rather than later.

Fergie on...

Wayne Rooney

ªWe have to define Wayne's role better because he sacrificed himself for the team last season. He would play centre-half if I asked himº

Mark Hughes

ªHe has left Blackburn at the right time because all the contracts are up next year. He's proved himself thereº

Carlos Queiroz

ªAll the changes at the club in terms of sports sciences over the last few years have been down to Carlosº

A new coach

ªOur coach Mike Phelan couldn't do much last season because of a knee problem but he's back now and can do more, so the coaching side is no problemº

Liverpool

ªThere is no particular pressure in terms of trying to beat Liverpool. We proved the point about overcoming Liverpool when I came to the clubº